压电阻抗技术监测固体推进剂老化研究

Impedance Characterization and Validation of Solid Propellant Based on Electro-Mechanical Impedance Method

关键词:  固体推进剂  压电阻抗法  机械阻抗  动态模量  老化

Key words:  Solid propellant  Electro-mechanical impedance method  Mechanical impedance  Dynamic modulus  Aging

摘要:

为了进一步研究表面粘贴式的主动传感技术——压电阻抗技术（EMI， Electro-Mechanical Impedance）监测固体推进剂的老化，构建了基于线粘弹杆结构的一维机电耦合模型，根据粘弹性波的理论与边界条件进行分析，建立一种线粘弹结构动态模量与其机械阻抗的表征关系，并对构建的机电耦合阻抗模型进行了数值计算及试验验证。针对HTPB固体推进剂开展高温热加速老化试验及压电主动激励试验，根据监测所得导纳频谱并通过提取结构机械阻抗进行分析，结果表明：压电陶瓷片与推进剂结构在高频机电耦合运动时（300kHz，280kHz）有明显的共振现象，结构固有频率高于机电耦合共振频率，并且在200kHz~400kHz频段与700kHz~900kHz频段内，结构机械阻抗频谱峰值会因固体推进剂的热老化时间增长而降低，且与热老化时间之间满足线性关系。由此可见，压电阻抗法能够与固体推进剂在力学性能上建立表征关系，通过得到固体推进剂结构机械阻抗能够监测其老化损伤。

Abstract:

In order to further study the aging of solid propellants by the Electro-mechanical impedance (EMI) method of surface paste, a one-dimensional electromechanical coupling model based on linear viscoelastic rod structure was constructed. Based on the theory of viscoelastic waves and boundary conditions, a relationship between the complex modulus of solid propellant and its mechanical impedance was established. Numerical calculation and experimental verification of the electromechanical impedance model were carried out. High-temperature thermal accelerated aging experiments and piezoelectric active excitation experiments for HTPB solid propellants were carried out, and according to the admittance spectrum obtained from monitoring, the structural mechanical impedance is extracted and analyzed. The results show that when the piezoelectric ceramic plate is coupled with the propellant structure, it has obvious resonance phenomenon when it moves at high frequency（300kHz，280kHz）. The natural frequency of the structure is higher than the electromechanical coupling resonance frequency. Moreover, The peak value of mechanical impedance spectrum in 200kHz ~ 400kHz and 700kHz ~ 900kHz will decrease with the increase of thermal aging time of solid propellant, and there is a linear relationship between the peak value and thermal aging time.It can be seen that the mechanical properties of the solid propellant can be characterized by the EMI method, by obtaining the mechanical impedance of the solid propellant structure, the aging damage can be monitored.